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Fish 'n' TRIMs.

Du Pasquier L - J. Biol. (2009)

Bottom Line: A novel diversified multigene family of tripartite-motif (TRIM) intracellular receptors with putative antiviral activity has been identified in teleost fish and published in BMC Biology.The history of these receptors involves ancient linkage to paralogs of the major histocompatibility complex, and the family has invertebrate precursors.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Basel, Institute of Zoology and Evolutionary Biology, Vesalgasse 1, Basel CH-4051, Switzerland. dupasquier@dial.eunet.ch

ABSTRACT
A novel diversified multigene family of tripartite-motif (TRIM) intracellular receptors with putative antiviral activity has been identified in teleost fish and published in BMC Biology. The history of these receptors involves ancient linkage to paralogs of the major histocompatibility complex, and the family has invertebrate precursors.

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Position of MHC and TRIM-B30.2 genes in the zebrafish genome. Green asterisks denote chromosomes with clusters of btr and ftr genes, and the number of these genes on the respective chromosome is shown below in green. MHC and MHC-paralogous genes are in magenta. Class II MHC genes have not been indicated; these are on chromosome 8 and not associated with any B30.2 TRIM. In addition, chromosome 16, which is rich in MHC-paralogous genes, has a few Trim-39-like genes not mentioned in [6]. In teleosts many rearrangements have caused the MHC elements that would normally be closely linked to be scattered; in this context, the loose linkage of TRIM genes to MHC genes is not unexpected. Modified from Figure 2 of [6].
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Figure 1: Position of MHC and TRIM-B30.2 genes in the zebrafish genome. Green asterisks denote chromosomes with clusters of btr and ftr genes, and the number of these genes on the respective chromosome is shown below in green. MHC and MHC-paralogous genes are in magenta. Class II MHC genes have not been indicated; these are on chromosome 8 and not associated with any B30.2 TRIM. In addition, chromosome 16, which is rich in MHC-paralogous genes, has a few Trim-39-like genes not mentioned in [6]. In teleosts many rearrangements have caused the MHC elements that would normally be closely linked to be scattered; in this context, the loose linkage of TRIM genes to MHC genes is not unexpected. Modified from Figure 2 of [6].

Mentions: Can any possible evolutionary scheme be derived from the position of ftr and btr genes on the chromosomes? Their presence on 16 of the 25 chromosomes suggests they are very mobile and can diversify independently of each other. However, their multiplicity may partly be due to the fact that, in addition to the two rounds of polyploidization common to gnathostomes, teleosts have had an extra round, which resulted in eight potential paralogous sets of chromosomes instead of the four found in other vertebrates. So do the numerous ftr and btr clusters match as many paralogous regions? Indeed, it seems that they are all located on chromosomes that also contain major histocompatibility complex (MHC) genes or their paralogs (Figure 1). This pattern fits with the hypothesis that, during the generation of the zebrafish genome, a region containing MHC and TRIM-B30.2 genes duplicated several times, in agreement with the above hypothesis of several genome duplications. If validated by statistical tests, this observation would suggest two things: first, that the ftr genes, which are present in a smaller number of clusters than the other TRIM-B30.2 genes, diversified later and specifically in teleosts from one of those early MHC-linked genes; and second, that the MHC-TRIM-B30.2 linkage is ancient and preceded the two rounds of genome duplication common to gnathostomes. Therefore, it is likely that relatives of TRIM-B30.2 existed in invertebrates.


Fish 'n' TRIMs.

Du Pasquier L - J. Biol. (2009)

Position of MHC and TRIM-B30.2 genes in the zebrafish genome. Green asterisks denote chromosomes with clusters of btr and ftr genes, and the number of these genes on the respective chromosome is shown below in green. MHC and MHC-paralogous genes are in magenta. Class II MHC genes have not been indicated; these are on chromosome 8 and not associated with any B30.2 TRIM. In addition, chromosome 16, which is rich in MHC-paralogous genes, has a few Trim-39-like genes not mentioned in [6]. In teleosts many rearrangements have caused the MHC elements that would normally be closely linked to be scattered; in this context, the loose linkage of TRIM genes to MHC genes is not unexpected. Modified from Figure 2 of [6].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2736664&req=5

Figure 1: Position of MHC and TRIM-B30.2 genes in the zebrafish genome. Green asterisks denote chromosomes with clusters of btr and ftr genes, and the number of these genes on the respective chromosome is shown below in green. MHC and MHC-paralogous genes are in magenta. Class II MHC genes have not been indicated; these are on chromosome 8 and not associated with any B30.2 TRIM. In addition, chromosome 16, which is rich in MHC-paralogous genes, has a few Trim-39-like genes not mentioned in [6]. In teleosts many rearrangements have caused the MHC elements that would normally be closely linked to be scattered; in this context, the loose linkage of TRIM genes to MHC genes is not unexpected. Modified from Figure 2 of [6].
Mentions: Can any possible evolutionary scheme be derived from the position of ftr and btr genes on the chromosomes? Their presence on 16 of the 25 chromosomes suggests they are very mobile and can diversify independently of each other. However, their multiplicity may partly be due to the fact that, in addition to the two rounds of polyploidization common to gnathostomes, teleosts have had an extra round, which resulted in eight potential paralogous sets of chromosomes instead of the four found in other vertebrates. So do the numerous ftr and btr clusters match as many paralogous regions? Indeed, it seems that they are all located on chromosomes that also contain major histocompatibility complex (MHC) genes or their paralogs (Figure 1). This pattern fits with the hypothesis that, during the generation of the zebrafish genome, a region containing MHC and TRIM-B30.2 genes duplicated several times, in agreement with the above hypothesis of several genome duplications. If validated by statistical tests, this observation would suggest two things: first, that the ftr genes, which are present in a smaller number of clusters than the other TRIM-B30.2 genes, diversified later and specifically in teleosts from one of those early MHC-linked genes; and second, that the MHC-TRIM-B30.2 linkage is ancient and preceded the two rounds of genome duplication common to gnathostomes. Therefore, it is likely that relatives of TRIM-B30.2 existed in invertebrates.

Bottom Line: A novel diversified multigene family of tripartite-motif (TRIM) intracellular receptors with putative antiviral activity has been identified in teleost fish and published in BMC Biology.The history of these receptors involves ancient linkage to paralogs of the major histocompatibility complex, and the family has invertebrate precursors.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Basel, Institute of Zoology and Evolutionary Biology, Vesalgasse 1, Basel CH-4051, Switzerland. dupasquier@dial.eunet.ch

ABSTRACT
A novel diversified multigene family of tripartite-motif (TRIM) intracellular receptors with putative antiviral activity has been identified in teleost fish and published in BMC Biology. The history of these receptors involves ancient linkage to paralogs of the major histocompatibility complex, and the family has invertebrate precursors.

Show MeSH